/*
  * Raw FLAC demuxer
  * Copyright (c) 2001 Fabrice Bellard
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 

 #include "libavcodec/flac.h"

 #include "avformat.h"

 #include "flac_picture.h"

 #include "internal.h"

 #include "rawdec.h"

 #include "oggdec.h"

 #include "vorbiscomment.h"

 #include "replaygain.h"

 #define SEEKPOINT_SIZE 18
 
 typedef struct FLACDecContext {
     int found_seektable;
 } FLACDecContext;
 
 static void reset_index_position(int64_t metadata_head_size, AVStream *st)
 {
     /* the real seek index offset should be the size of metadata blocks with the offset in the frame blocks */
     int i;
     for(i=0; i<st->nb_index_entries; i++) {
         st->index_entries[i].pos += metadata_head_size;
     }
 }
 

 static int flac_read_header(AVFormatContext *s)

 {

     int ret, metadata_last=0, metadata_type, metadata_size, found_streaminfo=0;
     uint8_t header[4];
     uint8_t *buffer=NULL;

     FLACDecContext *flac = s->priv_data;

     AVStream *st = avformat_new_stream(s, NULL);

     if (!st)
         return AVERROR(ENOMEM);

     st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
     st->codecpar->codec_id = AV_CODEC_ID_FLAC;

     st->need_parsing = AVSTREAM_PARSE_FULL_RAW;

     /* the parameters will be extracted from the compressed bitstream */
 

     /* if fLaC marker is not found, assume there is no header */

     if (avio_rl32(s->pb) != MKTAG('f','L','a','C')) {

         avio_seek(s->pb, -4, SEEK_CUR);

         return 0;

     }

 
     /* process metadata blocks */

     while (!avio_feof(s->pb) && !metadata_last) {

         if (avio_read(s->pb, header, 4) != 4)
             return AVERROR(AVERROR_INVALIDDATA);

         flac_parse_block_header(header, &metadata_last, &metadata_type,

                                    &metadata_size);
         switch (metadata_type) {
         /* allocate and read metadata block for supported types */
         case FLAC_METADATA_TYPE_STREAMINFO:

         case FLAC_METADATA_TYPE_CUESHEET:

         case FLAC_METADATA_TYPE_PICTURE:

         case FLAC_METADATA_TYPE_VORBIS_COMMENT:

         case FLAC_METADATA_TYPE_SEEKTABLE:

             buffer = av_mallocz(metadata_size + AV_INPUT_BUFFER_PADDING_SIZE);

             if (!buffer) {

                 return AVERROR(ENOMEM);

             }

             if (avio_read(s->pb, buffer, metadata_size) != metadata_size) {

                 RETURN_ERROR(AVERROR(EIO));

             }
             break;
         /* skip metadata block for unsupported types */
         default:

             ret = avio_skip(s->pb, metadata_size);

             if (ret < 0)
                 return ret;
         }
 
         if (metadata_type == FLAC_METADATA_TYPE_STREAMINFO) {

             uint32_t samplerate;
             uint64_t samples;
 

             /* STREAMINFO can only occur once */
             if (found_streaminfo) {

                 RETURN_ERROR(AVERROR_INVALIDDATA);

             }
             if (metadata_size != FLAC_STREAMINFO_SIZE) {

                 RETURN_ERROR(AVERROR_INVALIDDATA);

             }
             found_streaminfo = 1;

             st->codecpar->extradata      = buffer;
             st->codecpar->extradata_size = metadata_size;

             buffer = NULL;
 

             /* get sample rate and sample count from STREAMINFO header;
              * other parameters will be extracted by the parser */

             samplerate = AV_RB24(st->codecpar->extradata + 10) >> 4;
             samples    = (AV_RB64(st->codecpar->extradata + 13) >> 24) & ((1ULL << 36) - 1);

 
             /* set time base and duration */

             if (samplerate > 0) {
                 avpriv_set_pts_info(st, 64, 1, samplerate);
                 if (samples > 0)
                     st->duration = samples;

             }

         } else if (metadata_type == FLAC_METADATA_TYPE_CUESHEET) {
             uint8_t isrc[13];
             uint64_t start;
             const uint8_t *offset;

             int i, chapters, track, ti;

             if (metadata_size < 431)

                 RETURN_ERROR(AVERROR_INVALIDDATA);

             offset = buffer + 395;
             chapters = bytestream_get_byte(&offset) - 1;
             if (chapters <= 0)

                 RETURN_ERROR(AVERROR_INVALIDDATA);

             for (i = 0; i < chapters; i++) {
                 if (offset + 36 - buffer > metadata_size)

                     RETURN_ERROR(AVERROR_INVALIDDATA);

                 start = bytestream_get_be64(&offset);
                 track = bytestream_get_byte(&offset);
                 bytestream_get_buffer(&offset, isrc, 12);
                 isrc[12] = 0;
                 offset += 14;
                 ti = bytestream_get_byte(&offset);

                 if (ti <= 0) RETURN_ERROR(AVERROR_INVALIDDATA);

                 offset += ti * 12;

                 avpriv_new_chapter(s, track, st->time_base, start, AV_NOPTS_VALUE, isrc);
             }

             av_freep(&buffer);

         } else if (metadata_type == FLAC_METADATA_TYPE_PICTURE) {

             ret = ff_flac_parse_picture(s, buffer, metadata_size);

             av_freep(&buffer);
             if (ret < 0) {
                 av_log(s, AV_LOG_ERROR, "Error parsing attached picture.\n");
                 return ret;
             }

         } else if (metadata_type == FLAC_METADATA_TYPE_SEEKTABLE) {
             const uint8_t *seekpoint = buffer;
             int i, seek_point_count = metadata_size/SEEKPOINT_SIZE;
             flac->found_seektable = 1;
             if ((s->flags&AVFMT_FLAG_FAST_SEEK)) {
                 for(i=0; i<seek_point_count; i++) {
                     int64_t timestamp = bytestream_get_be64(&seekpoint);
                     int64_t pos = bytestream_get_be64(&seekpoint);
                     /* skip number of samples */
                     bytestream_get_be16(&seekpoint);
                     av_add_index_entry(st, pos, timestamp, 0, 0, AVINDEX_KEYFRAME);
                 }
             }
             av_freep(&buffer);
         }
         else {
 

             /* STREAMINFO must be the first block */
             if (!found_streaminfo) {

                 RETURN_ERROR(AVERROR_INVALIDDATA);

             }
             /* process supported blocks other than STREAMINFO */
             if (metadata_type == FLAC_METADATA_TYPE_VORBIS_COMMENT) {

                 AVDictionaryEntry *chmask;
 

                 ret = ff_vorbis_comment(s, &s->metadata, buffer, metadata_size, 1);
                 if (ret < 0) {

                     av_log(s, AV_LOG_WARNING, "error parsing VorbisComment metadata\n");

                 } else if (ret > 0) {
                     s->event_flags |= AVFMT_EVENT_FLAG_METADATA_UPDATED;

                 }

 
                 /* parse the channels mask if present */
                 chmask = av_dict_get(s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", NULL, 0);
                 if (chmask) {
                     uint64_t mask = strtol(chmask->value, NULL, 0);
                     if (!mask || mask & ~0x3ffffULL) {
                         av_log(s, AV_LOG_WARNING,
                                "Invalid value of WAVEFORMATEXTENSIBLE_CHANNEL_MASK\n");
                     } else {

                         st->codecpar->channel_layout = mask;

                         av_dict_set(&s->metadata, "WAVEFORMATEXTENSIBLE_CHANNEL_MASK", NULL, 0);
                     }
                 }

             }
             av_freep(&buffer);
         }
     }
 

     ret = ff_replaygain_export(st, s->metadata);
     if (ret < 0)
         return ret;
 

     reset_index_position(avio_tell(s->pb), st);

     return 0;

 
 fail:
     av_free(buffer);
     return ret;

 }
 

 static int raw_flac_probe(AVProbeData *p)
 {
     if ((p->buf[2] & 0xF0) == 0)    // blocksize code invalid
         return 0;
     if ((p->buf[2] & 0x0F) == 0x0F) // sample rate code invalid
         return 0;
     if ((p->buf[3] & 0xF0) >= FLAC_MAX_CHANNELS + FLAC_CHMODE_MID_SIDE << 4)
         // channel mode invalid
         return 0;
     if ((p->buf[3] & 0x06) == 0x06) // bits per sample code invalid
         return 0;
     if ((p->buf[3] & 0x01) == 0x01) // reserved bit set
         return 0;
     return AVPROBE_SCORE_EXTENSION / 4 + 1;
 }
 

 static int flac_probe(AVProbeData *p)
 {

     if ((AV_RB16(p->buf) & 0xFFFE) == 0xFFF8)
         return raw_flac_probe(p);

     /* file header + metadata header + checked bytes of streaminfo */
     if (p->buf_size >= 4 + 4 + 13) {
         int type           = p->buf[4] & 0x7f;
         int size           = AV_RB24(p->buf + 5);
         int min_block_size = AV_RB16(p->buf + 8);
         int max_block_size = AV_RB16(p->buf + 10);
         int sample_rate    = AV_RB24(p->buf + 18) >> 4;
 

         if (memcmp(p->buf, "fLaC", 4))
             return 0;
         if (type == FLAC_METADATA_TYPE_STREAMINFO &&

             size == FLAC_STREAMINFO_SIZE          &&
             min_block_size >= 16                  &&
             max_block_size >= min_block_size      &&
             sample_rate && sample_rate <= 655350)
             return AVPROBE_SCORE_MAX;

         return AVPROBE_SCORE_EXTENSION;

     }
 
     return 0;

 }
 

 static av_unused int64_t flac_read_timestamp(AVFormatContext *s, int stream_index,
                                              int64_t *ppos, int64_t pos_limit)
 {
     AVPacket pkt, out_pkt;
     AVStream *st = s->streams[stream_index];

     AVCodecParserContext *parser;

     int ret;

     int64_t pts = AV_NOPTS_VALUE;

 
     if (avio_seek(s->pb, *ppos, SEEK_SET) < 0)
         return AV_NOPTS_VALUE;
 
     av_init_packet(&pkt);

     parser = av_parser_init(st->codecpar->codec_id);

     if (!parser){

         return AV_NOPTS_VALUE;
     }

     parser->flags |= PARSER_FLAG_USE_CODEC_TS;

 
     for (;;){
         ret = ff_raw_read_partial_packet(s, &pkt);
         if (ret < 0){
             if (ret == AVERROR(EAGAIN))
                 continue;

             else {
                 av_packet_unref(&pkt);
                 av_assert1(!pkt.size);
             }

         }
         av_init_packet(&out_pkt);

         av_parser_parse2(parser, st->internal->avctx,

                          &out_pkt.data, &out_pkt.size, pkt.data, pkt.size,
                          pkt.pts, pkt.dts, *ppos);

         av_packet_unref(&pkt);

         if (out_pkt.size){
             int size = out_pkt.size;

             if (parser->pts != AV_NOPTS_VALUE){

                 // seeking may not have started from beginning of a frame
                 // calculate frame start position from next frame backwards

                 *ppos = parser->next_frame_offset - size;
                 pts = parser->pts;
                 break;

             }

         } else if (ret < 0)
             break;

     }

     av_parser_close(parser);
     return pts;

 }
 

 static int flac_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {
     int index;
     int64_t pos;
     AVIndexEntry e;
     FLACDecContext *flac = s->priv_data;
 
     if (!flac->found_seektable || !(s->flags&AVFMT_FLAG_FAST_SEEK)) {
         return -1;
     }
 
     index = av_index_search_timestamp(s->streams[0], timestamp, flags);
     if(index<0 || index >= s->streams[0]->nb_index_entries)
         return -1;
 
     e = s->streams[0]->index_entries[index];
     pos = avio_seek(s->pb, e.pos, SEEK_SET);
     if (pos >= 0) {
         return 0;
     }
     return -1;
 }
 

 AVInputFormat ff_flac_demuxer = {

     .name           = "flac",
     .long_name      = NULL_IF_CONFIG_SMALL("raw FLAC"),
     .read_probe     = flac_probe,
     .read_header    = flac_read_header,
     .read_packet    = ff_raw_read_partial_packet,

     .read_seek      = flac_seek,

     .read_timestamp = flac_read_timestamp,

     .flags          = AVFMT_GENERIC_INDEX,
     .extensions     = "flac",

     .raw_codec_id   = AV_CODEC_ID_FLAC,

     .priv_data_size = sizeof(FLACDecContext),

 };